The present invention relates to apparatus for assisting makeup.
Apparatus is known, in particular from international application WO 96/21201, comprising an acquisition unit for acquiring a 2D image of a face and image processing means to display the virtual application of makeup on the face.
The Dec. 21, 1998 number of The Nikkei Weekly magazine discloses work enabling a made-up face to be displayed as a 3D image.
Known apparatuses do not make it possible to take account, amongst other things, of the lighting conditions in which a made-up subject is going to move around.
In particular, a person can make up at home under artificial light and then move outside, such that the rendering of the makeup is different.
Finally, known apparatuses are poorly adapted at simulating the application of a makeup that masks little, is transparent, or diffuses slightly, and they take no account of the physical phenomena of light interaction between the skin and the cosmetic.
Thus, simulating the application of glossy or shiny makeup is not satisfactory.
There exists a need to simulate the application of makeup while taking account of the ambient lighting in which the made-up person is going to move about, thus enabling a person to make up or to select makeup as a function of particular lighting conditions.
A particular object of the invention is to provide apparatus for assistance in makeup that makes it easy to simulate in realistic manner the application of a given makeup, e.g. on the face, for various lighting conditions.
The novel apparatus of the invention for assistance in makeup comprises:
a measurement unit for measuring local phenomena of light interaction with a zone to be made up and/or treated;
a database relating to the BRDF of various cosmetic and/or care products;
selector means enabling a product to be selected;
calculation means for calculating the resulting BRDF of the zone virtually made up or treated with the product, on the basis of measurements previously taken and on the basis of information taken from said database and relating to the BRDF of the selected makeup product; and
display means for displaying the zone virtually made up or treated in this way as a result of the previously calculated resulting BRDF.
BRDF stands for bidirectional reflectance distribution function, it is well known to specialists in synthesized images, and it depends on various geometrical and physical parameters associated with the light source used, the nature of the illuminated target, and the conditions of illumination and of observation.
This function makes it possible in particular to take account of the angle of incidence of the light, the angle of observation, the nature of the illuminated skin, and its surface appearance.
By means of the invention, it is possible to simulate virtual application of a cosmetic and/or care product while taking account in particular of the fact that the color at a point on the face depends on the geometrical extent of the light source, and thus on the directions of incidence of light on the illuminated surface, on the spectral characteristics of said light, on the nature of the illuminated surface, and on the direction from which it is observed.
The apparatus of the invention for assistance in makeup thus makes it possible to take into consideration the goniochromatic aspects of the makeup and/or care product used, in particular the way its reflectance, its transparency, and its masking power vary as a function of the direction of observation.
The invention also makes it possible to take account of light diffusion through the makeup.
The invention thus makes it possible to simulate optical effects specific to the makeup used, for example its mattness, its gloss, or its iridescence.
In a preferred implementation of the invention, the apparatus includes calculator means organized to calculate the BRDF parameters of the zone to be made up and/or treated on the basis of the measurements performed.
Thus, a relatively limited number of measurement points within the zone to be made up or treated can suffice, the BRDF parameters being determined by the calculation means on the basis of the measurements performed.
Preferably, the parameters used for calculating BRDF are the absorption coefficient xcexca(xcex), the diffusion coefficient xcexcs(xcex), the diffusion anisotropy coefficient q, the refractive index n(xcex), and the roughness coefficient m, xcex being the wavelength of the light.
Advantageously, the skin parameters xcexca(xcex) and xcexcs(xcex) are calculated on the basis of a model using as its variables the melanin content in the epidermis, the blood content in the dermis, and its degree of oxidation.
In a particular embodiment, the apparatus for assistance in makeup includes a control member enabling the user to input information associated with the way in which the cosmetic product is to be applied to the face.
The control member may comprise a force feedback mouse.
Thus, the user can determine the intensity of makeup by exerting greater or smaller force on the control member.
This makes it possible to simulate making up by means of a pencil, for example, which leaves a colored mark of greater or lesser intensity when it is pressed with greater or lesser force against the skin, the intensity corresponding to greater or smaller thicknesses and densities of the makeup.
Advantageously, the apparatus for assistance in makeup includes an expert system which, on the basis of data provided by the user, selects a makeup product as a function of predetermined criteria, in order to match the color of the makeup to that of the eyes or the hair of the user, for example.
On this topic, reference can be made to European patent application EP-A-0 646 339, for example.
Advantageously, the display means comprise stereoscopic display means so as to make the simulation more realistic.
In a particular embodiment, the measurement unit includes a sphere provided with means for lighting the subject present in the sphere and means for acquiring images that are arranged to enable local data of the subject to be acquired to be treated.
The measurement unit may include apparatus for acquiring the topography of the face, which apparatus is selected from the following kinds of apparatus: stereo viewing apparatus that operates by simultaneous acquisition of a profile view and a front view; laser triangular apparatus; fringe projection apparatus.
Advantageously, the measurement unit includes apparatus for acquiring the spectral reflectance of the face, enabling the color of the face to be determined at a set of points, at a given illumination angle, and at a given observation direction.
The measurement unit can detect dyschromias, e.g. acne rosacea or areas of pigmentation.
Advantageously, the database relating to the BRDF of cosmetic and/or care products comprises a database relating to the BRDF of products selected from the following list: foundations, lipsticks, cheek blushers, eyeliners, mascara, nail varnishes, hair dyes, skin coloring products, semi-permanent makeup products (e.g. for tattoos).
Advantageously, said database includes information relating to the BRDF of the products for different thicknesses of deposit.
Advantageously, the measurement unit is associated with shape recognition means enabling parts of the face to be identified.
Preferably, the shape recognition means are arranged to detect wrinkles or folds in the skin.
Thus, the presence of wrinkles on the face is advantageously taken into account when calculating the resulting BRDF in order to represent the fact, for example, that the makeup tends to accumulate in the creases formed by the wrinkles.
The invention also provides an assembly comprising apparatus for assistance in makeup as defined above together with apparatus enabling makeup to be dispensed that has a predetermined BRDF, as selected by the apparatus for assistance in makeup.
Such an assembly can advantageously be present at a site where cosmetics are sold.
The invention also provides a method enabling the application of a cosmetic and/or a care product to be simulated, the method comprising the steps consisting in:
measuring local phenomena of light interaction with a zone of the subject for known lighting and observation conditions;
using the measurements performed to calculate parameters enabling the BRDF of said zone to be calculated as a function of given lighting and observation conditions;
selecting a cosmetic and/or care product for which the parameters serving for calculating the BRDF are known;
calculating the BRDF that result on said zone of the subject after said product has been applied; and
displaying said virtually made-up and/or treated zone on the basis of the previously calculated resulting BRDF for the given lighting and observation conditions.
In a particular implementation, the parameters enabling the BRDF to be calculated are the absorption coefficient xcexca(xcex) and the diffusion coefficient xcexcs(xcex), the diffusion anisotropy factor a, the refractive index n(xcex), and the roughness coefficient m.
Preferably, the invention includes the step consisting in selecting the lighting conditions under which the virtually made-up and/or treated zone is to be displayed.
Thus, the user can visualize the rendition of makeup under various lighting conditions, and can choose the makeup that is best suited to a given event.